android框架：Retrofit + RxJava2.0 + Lambda

引言

前面介绍过lambda和RxJava的使用后，那么下面我们将进入Retrofit + RxJava2.0 + Lambda三个框架的联合使用．

当然中间涉及注解相关的可以参考以下：
Annotation注解APT(一):什么是Annotation注解
Annotation注解APT(二):自定义注解
Annotation注解APT(三):依赖注入是什么
Annotation注解APT(四):依赖注入框架Dagger
Annotation注解APT(五):注入框架ButterKnife

一．Retrofit

＂A type-safe HTTP client for Android and Java＂这是官网的描述，也就是说Retrofit是一个类型安全的http客户端，那么如何理解和使用，我们来通过一个简单的demo开始：
为方便网络请求测试，将使用这个url:

http://www.izaodao.com/API/AppFiftyToneGraph/videoLink

可以在浏览器中拉下数据看下：

{  "ret": 1,  "msg": "成功",  "data": [    {      "id": 0,      "name": "qianyan.mp4",      "url": "https://bj.bcebos.com/course-mct/media/qianyan.mp4?authorization=bce-auth-v1%2Fde89d2e06dd7443a9e4422d5b3fb4eea%2F2017-06-24T09%3A02%3A16Z%2F6000%2F%2Fc26012cc47193c73f00bffda032373c1d189d2b3f64253bcc926860ee33b4901",      "title": "前言"    },    //这里省略   ．．．．．    {      "id": 18,      "name": "50yinjieshu.mp4",      "url": "https://bj.bcebos.com/course-mct/media/50yinjieshu.mp4?authorization=bce-auth-v1%2Fde89d2e06dd7443a9e4422d5b3fb4eea%2F2017-06-24T09%3A02%3A21Z%2F6000%2F%2F33a50f2217e60537044a49b8a69ea72f3bfc684288a67c1d2e63e2b808debe95",      "title": "结束"    }  ]}

可以看出，这是一个标准json格式，因此我们在添加库的时候，还应该添加json的解析工厂库．
开始，先配置app build.gradle

dependencies {    compile fileTree(dir: 'libs', include: ['*.jar'])    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {        exclude group: 'com.android.support', module: 'support-annotations'    })    compile 'com.android.support:appcompat-v7:25.3.1'    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha7'    testCompile 'junit:junit:4.12'    compile 'com.squareup.retrofit2:retrofit:2.2.0'  //Retrofit    compile 'com.squareup.retrofit2:converter-gson:2.2.0'    //GsonConverterFactory}

根据json数据格式,我们新建要保存数据的bean:

public class RetrofitEntity {    private int ret;               //对应json中的ret字段    private String msg;            //对应json中的msg字段    private List<Subject> data;    //对应json中的data字段    public int getRet() {        return ret;    }    public void setRet(int ret) {        this.ret = ret;    }    public String getMsg() {        return msg;    }    public void setMsg(String msg) {        this.msg = msg;    }    public List<Subject> getData() {        return data;    }    public void setData(List<Subject> data) {        this.data = data;    }}

public class Subject {    private int id;                //对应json中的id字段    private String name;           //对应json中的name字段    private String title;          //对应json中的title字段    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }}

请求接口类：

public interface MyApiEndpointInterface {    @POST("AppFiftyToneGraph/videoLink")    Call<RetrofitEntity> getAllVedio(@Body boolean once_no);}

测试１，异步方法（enqueue）

    static String BASE_URL = "http://www.izaodao.com/Api/";    //retrofit异步请求    public void test_1(){        Retrofit retrofit = new Retrofit.Builder()                .baseUrl(BASE_URL)                .addConverterFactory(GsonConverterFactory.create())                .build();        MyApiEndpointInterface apiService = retrofit.create(MyApiEndpointInterface.class);        Call<RetrofitEntity> call = apiService.getAllVedio(true);        mycall = call;        call.enqueue(new Callback<RetrofitEntity>() {            @Override            public void onResponse(Call<RetrofitEntity> call, Response<RetrofitEntity> response) {                RetrofitEntity entity = response.body();                if(entity.getRet() == 1){                    Log.i("tag", "onResponse----->" + entity.getMsg());                    List<Subject> data = entity.getData();                    for(Subject subject : data){                        Log.i("tag", "----------------------------------------------" + subject.getId());                        Log.i("tag", "name :" + subject.getName());                        Log.i("tag", "title:" + subject.getTitle());                    }                }            }            @Override            public void onFailure(Call<RetrofitEntity> call, Throwable t) {                Log.i("tag", "onFailure----->" + t.toString());            }        });    }

测试２，同步方法（）

 static String BASE_URL = "http://www.izaodao.com/Api/";    //同步请求，不能在ｕｉ线程调用此方法    public void test_2(){        Retrofit retrofit = new Retrofit.Builder()                .baseUrl(BASE_URL)                .addConverterFactory(GsonConverterFactory.create())                .build();        MyApiEndpointInterface apiService = retrofit.create(MyApiEndpointInterface.class);        Call<RetrofitEntity> call = apiService.getAllVedio(true);        mycall = call;        try {            Response<RetrofitEntity> response = call.execute();            if(response != null){                RetrofitEntity entity = response.body();                if(entity.getRet() == 1){                    Log.i("tag", "onResponse----->" + entity.getMsg());                    List<Subject> data = entity.getData();                    for(Subject subject : data){                        Log.i("tag", "----------------------------------------------" + subject.getId());                        Log.i("tag", "name :" + subject.getName());                        Log.i("tag", "title:" + subject.getTitle());                    }                }            }        }catch (Exception e){            e.printStackTrace();        }    }

二.Retrofit + RxJava2.0

RxJava可以参考这篇文章：RxJava2：observeOn和subscribeOn的使用

先添加对RxJava的依赖：

dependencies {    compile fileTree(dir: 'libs', include: ['*.jar'])    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {        exclude group: 'com.android.support', module: 'support-annotations'    })    compile 'com.android.support:appcompat-v7:25.3.1'    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha7'    testCompile 'junit:junit:4.12'    //rxjava    compile 'io.reactivex.rxjava2:rxjava:2.0.1'    compile 'io.reactivex.rxjava2:rxandroid:2.0.1'    compile 'com.squareup.retrofit2:retrofit:2.2.0'           //Retrofit    compile 'com.squareup.retrofit2:converter-gson:2.2.0'    //GsonConverterFactory    compile 'com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0'}

MyApiEndpointInterface中添加支持接口：

public interface MyApiEndpointInterface {    @POST("AppFiftyToneGraph/videoLink")    Call<RetrofitEntity> getAllVedio(@Body boolean once_no);    @POST("AppFiftyToneGraph/videoLink")    Observable<RetrofitEntity> getAllVedioBy(@Body boolean once_no);}

测试３

static String BASE_URL = "http://www.izaodao.com/Api/";    //RxJava + Retrofit    public void test_3(){        Retrofit retrofit = new Retrofit.Builder()                .baseUrl(BASE_URL)                .addConverterFactory(GsonConverterFactory.create())                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())                .build();        MyApiEndpointInterface apiService = retrofit.create(MyApiEndpointInterface.class);        Observable<RetrofitEntity> observable = apiService.getAllVedioBy(true);        observable.subscribeOn(Schedulers.io())                .observeOn(AndroidSchedulers.mainThread())                .subscribe(new Observer<RetrofitEntity>() {                    @Override                    public void onSubscribe(Disposable d) {                    }                    @Override                    public void onNext(RetrofitEntity entity) {                        if(entity.getRet() == 1){                            Log.i("tag", "onResponse----->" + entity.getMsg());                            List<Subject> data = entity.getData();                            for(Subject subject : data){                                Log.i("tag", "----------------------------------------------" + subject.getId());                                Log.i("tag", "name :" + subject.getName());                                Log.i("tag", "title:" + subject.getTitle());                            }                        }                    }                    @Override                    public void onError(Throwable e) {                    }                    @Override                    public void onComplete() {                        Log.i("tag", "onComplete");                    }                });    }

三.Retrofit + RxJava2.0 + Lambda

lambda的思想，个人理解是对于确定的类型，可以像匿名内部内一样使用．
还是一样，先配置：lambda：在android studio中的配置和使用lambda表达式

对于测试３，如果我们这样使用：
测试４：

 static String BASE_URL = "http://www.izaodao.com/Api/";    public void test_4(){        Retrofit retrofit = new Retrofit.Builder()                .baseUrl(BASE_URL)                .addConverterFactory(GsonConverterFactory.create())                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())                .build();        MyApiEndpointInterface apiService = retrofit.create(MyApiEndpointInterface.class);        Observable<RetrofitEntity> observable = apiService.getAllVedioBy(true);        observable.subscribeOn(Schedulers.io())                .observeOn(AndroidSchedulers.mainThread())                .subscribe(new Consumer<RetrofitEntity>() {                    @Override                    public void accept(RetrofitEntity entity) throws Exception {                        if(entity.getRet() == 1){                            Log.i("tag", "onResponse----->" + entity.getMsg());                            List<Subject> data = entity.getData();                            for(Subject subject : data){                                Log.i("tag", "----------------------------------------------" + subject.getId());                                Log.i("tag", "name :" + subject.getName());                                Log.i("tag", "title:" + subject.getTitle());                            }                        }                    }                });｝

因此再变成测试５：

    static String BASE_URL = "http://www.izaodao.com/Api/";    public void test_4(){        Retrofit retrofit = new Retrofit.Builder()                .baseUrl(BASE_URL)                .addConverterFactory(GsonConverterFactory.create())                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())                .build();        MyApiEndpointInterface apiService = retrofit.create(MyApiEndpointInterface.class);        Observable<RetrofitEntity> observable = apiService.getAllVedioBy(true);        observable.subscribeOn(Schedulers.io())                .observeOn(AndroidSchedulers.mainThread())                .subscribe(entity -> {                        if(entity.getRet() == 1){                            Log.i("tag", "onResponse----->" + entity.getMsg());                            List<Subject> data = entity.getData();                            for(Subject subject : data){                                Log.i("tag", "----------------------------------------------" + subject.getId());                                Log.i("tag", "name :" + subject.getName());                                Log.i("tag", "title:" + subject.getTitle());                            }                        }                },onError->{                    Log.i("tag", "onError:" + onError.getMessage());                });    }

这样是不是很好理解了．

如果想继续深入了解Retrofit + Rxjava,可以看这个专栏：
http://blog.csdn.net/column/details/13297.html

一．@SerializedName注解

上面的实例中RetrofitEntity和Subject中的元素和json中的各个字段是一一对应的，如果json中字段的名称发生了变化，那么我们的代码及调用接口都要变化，这样使用起来很不方便，如果我们使用@SerializedName注解就很方便了，只需要改字段名称即可：

public class RetrofitEntity {    @SerializedName("ret")    private int ret_num;               //对应json中的ret字段    @SerializedName("msg")    private String message;            //对应json中的msg字段    @SerializedName("data")    private List<Subject> data;    //对应json中的data字段    public int getRet() {        return ret_num;    }    public void setRet(int ret) {        this.ret_num = ret;    }    public String getMsg() {        return message;    }    public void setMsg(String msg) {        this.message = msg;    }    public List<Subject> getData() {        return data;    }    public void setData(List<Subject> data) {        this.data = data;    }}

是不是很方便？